The following description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
Treatment of radioactive waste has always been a challenge. Part of the reasons is that the radioactive waste usually remains hazardous for a long period of time (e.g., 40 years, 100 years) before it can be released. Until the hazardous level of the waste becomes acceptable, the waste is usually being treated in an isolated environment.
The Hanford Site, located in southeastern Washington State, was the largest of three defense production sites in the U.S. Over the span of 40 years, it was used to produce 64 metric tons of plutonium, helping end World War II and playing a major role in military defense efforts during the Cold War. As a result, 56 million gallons of radioactive and chemical wastes are now stored in 177 underground tanks on the Hanford Site.
To address this challenge, the U.S. Department of Energy contracted a US Contractor, to design and build the world's largest radioactive waste treatment plant. The Hanford Waste Treatment and Immobilization Plant (WTP), also known as the “Vit Plant,” will use vitrification to immobilize most of Hanford's dangerous waste.
Some efforts have been made to monitor the physical and/or chemical status of highly radioactive environment. For example, Ball et al., in a publication titled “Task 1-Instrumentation in VHTRs for Process Heat Applications,” published in October 2010, discloses a device, Thermocouple penetration assembly, to monitor the temperature distribution of the core graphite and metal components in high-radiation environment. In Ball's thermocouple penetration assembly, sheathed thermocouples are located in a protective tube that prevents the thermocouples from directly contacting the hazardous environment. However, Ball does not provide any means to replace the sheathed thermocouple can be replaceable without disassembling the entire thermocouple penetration assembly.
Similarly, international patent application WO 2014/001714 A1 to Pinet, titled “Device for detecting the level of a liquid contained in a container,” published Jan. 3, 2014, discusses a device for detecting the level of liquid contained in a cooling pool of spent fuel of a nuclear reactor. Specifically, Pinet discloses a temperature sensor comprising an optical fiber with multiple Bragg gratings. However, Pinet's device is limited to measure the temperature and the water level in the radioactive container.
Other efforts have been made to monitor physical and/or chemical status of highly radioactive environment other than temperature. For example, U.S. Pat. No. 6,004,070 to Van Camp, titled “Waste storage containment cell, method of operating, and apparatus therefore,” issued Dec. 21, 1999, discusses a covered landfill waste containment cell with a leak detection system. In Van Camp, the containment cell includes numerous leak monitor conduits surrounding the cell. The leak monitor conduit may contain a messenger cable or control cable, which can be a photosensitive fiber optic or other electronic devices. However, Van Camp only discloses that the conduits are embedded into the floor of the containment cells. Furthermore, the conduits include perforations on its surface to detect water leaked into the bottom of the cell so that the fiber optics in the conduits is directly exposed to the radioactive environment.
Another U.S. Pat. No. 6,648,552 to Smith et al., titled “Sensor system for buried waste containment sites,” issued Nov. 18, 2003, discusses a sensor system for buried waste containment sites. In Smith et al., one or more access tubes are disposed in or below the barriers of the containment sites and sensor devices are disposed in the access tubes. The access tubes provide protection for the sensor device. Through the access tubes, sensors can be removed and deployed. Furthermore, one or more ends of the tubes containing sensors are exposed on the surface of the ground, by which sensor arrays can be easily installed or replaced. Yet, Smith only discloses that sensor devices are buried in the barriers of containment sites. Also, Smith's device is largely limited to the detection of radiation leakage through the barriers.
Thus, there is a need to determine the condition, in real time for operational safety, of certain Black Cells where pulse jet mixers mix the radioactive waste. The current design does not provide for monitoring or control. These Black Cells are highly radioactive and will be sealed for the 40-year operating life of the facility. New innovative health/status monitoring solutions are therefore needed.
All publications identified herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
In some embodiments, the numbers expressing quantities of ingredients, properties such as concentration, reaction conditions, and so forth, used to describe and claim certain embodiments of the invention are to be understood as being modified in some instances by the term “about.” Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
Unless the context dictates the contrary, all ranges set forth herein should be interpreted as being inclusive of their endpoints, and open-ended ranges should be interpreted to include only commercially practical values. Similarly, all lists of values should be considered as inclusive of intermediate values unless the context indicates the contrary.
The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value with a range is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all Markush groups used in the appended claims.